The notion of general cognitive ability (or "intelligence") is explored and why the time might now be ripe for educators to re-consider the power offered by a general intellectual capacity which is itself amenable to educational influence. We review existing knowledge concerning general intelligence, including the cohabitation of general and special abilities, cognitive modules, development, and evidence for plasticity of the general processor. We examine why this knowledge is generally absent from educational practice and present a number of models that attempt to synthesise the main aspects of current psychological theories. We explore how the models might be used in educational applications and look at examples of effective cognitive stimulation considering both practicalities and theoretical notions of what in our cognitive models is affected by stimulation. We discuss finally the possible political, cultural and social barriers to the inclusion of general ability as central to educational aims. (Contains 1 figure and 1 table.)